1. Field of Invention
The present invention relates to a photosensitive resin composition for a black matrix, and a black matrix, a color filter and a liquid crystal display (LCD) by using the same. More particularly, the present invention relates to a photosensitive resin having excellent temporal stability and heat resistance for a black matrix, and a color filter and a liquid crystal display (LCD) by using the black matrix.
2. Description of Related Art
A color filter has been widely applied on many fields such as color liquid crystal display (LCD) devices, color faxes, color cameras and the like. As the demand for office instruments such as the color LCD devices continuously increases and the related technologies have a drastic advance, resulting in the higher resolution requirement.
As everyone knows, a photosensitive resin composition has been widely applied to the process of the color filter, desired color pixels, the black matrix (or called as the shielding layer) and the like can be formed on a substrate by the photosensitive resin composition. In briefly, the pigments are dispersed in the photosensitive resin composition and coated onto a transparent substrate. After the steps of exposure, development, postbake and the like, the photosensitive resin composition can be made to the color pixels, the black matrix and so on. Recently, for enhancing the contrast and displaying quality of the LCD, the black matrix is formed in the gaps of strips and dots by using photolithography process, for example, thereby preventing the problems of less contrast and less color purity (chromaticity) resulted from the light leakage among the pixels.
Since the requirement for the shielding ability of the black matrix is more stringent, one of the solutions is to increase the amount of the black pigment, so as to increase the shielding ability, sensitivity, adhesiveness and to reduce the residue of the black matrix. For example, a photoresensitive resin composition for color filter is disclosed in Japanese Patent Laid-Open No. 2006-259716, which includes a pigment, an alkali-soluble resin, a photoinitiator, a reactive monomer having two functional groups and an organic solvent. The aforementioned reactive monomer is used to improve the reaction of those compounds, for forming highly fine patterns and increasing sensitivity, adhesiveness and reducing the residue of the black matrix.
Moreover, an alkali-soluble resin and a photoresensitive resin composition containing the same are disclosed in Japanese Patent Laid-Open No. 2011-122151. The alkali-soluble resin has a specific structure. When the photoresensitive resin composition that includes such alkali-soluble resin is applied in the process of the black matrix, sensitivity and adhesiveness of the photoresensitive resin composition that contains high amount of the black pigment can be elevated, so as to form ultra-fine wiring patterns.
The photoresensitive resin composition that contains high amount of the black pigment can satisfy the requirement of this industry. However, there are some problems existed in the photoresensitive resin composition, for example, such photoresensitive resin composition has worse temporal stability for it is sensitive to heat during the storage under a highly thermal environment.
Moreover, a touch panel is easy to use and widely applied in various end products of consumer electronics. However, in the condition of the touch panel more often working under direct exposure of the sunlight, the highly thermal environment will influence the black matrix, and the thermal ability and the display quality of the screen will be worse.
Accordingly, it is necessary to provide a photosensitive resin composition for exhibiting better temporal stability and thermal resistance and improving shortcomings of temporal instability and worse thermal resistance of the prior photosensitive resin composition after being heated.